1. Field of the Invention
This invention relates to an improved copying apparatus. More particularly, it relates to a two-mode copying apparatus having an original supporting carriage (the term "original supporting carriage" used here covers a stationary original holder and a reciprocable original holder) for supporting thereon a stationary original (which means an original held on the original supporting carriage) and an original feeding system for feeding originals past an exposure station.
2. Description of the Prior Art
Heretofore, various attempts have been made to improve the handling originals in copying machines. It has also been proposed to add an automatic sheet original feeding device to an ordinary copying machine by noticing the fact that the handling of originals in sheet original copying machines is ready to be automatized. An example is disclosed in Japanese Patent Publication No. 26068/1976. This is a copying machine simply equipped with a sheet original feeding device, but automatization of such feeding device has also been put into practice. An embodiment of this system according to the prior art is shown in FIGS. 1 and 2 of the accompanying drawings. Designated by a is an original supporting carriage on which a thick original, if to be copied, may be placed by opening a pressure cover a'. Depression of the copy button b causes automatic reciprocation of the original carriage a, thus providing a copy. On one end of the original supporting carriage, a sheet original feeding station c is formed integrally therewith, so that sheet originals may be inserted into this feeding station to thereby obtain copies. This is excellent in that it uses an original illumination system and an optical system in common for both types of originals, whereas the original supporting carriage a integral with the sheet feeding station c is so heavy that a problem tends to occur when effecting the reciprocation of the original supporting carriage smoothly and accurately. Further, a model equipped with an automatic sheet original feeding device would be too heavy to effect the reciprocation of the carriage. Thus, in order that the reciprocation may be effected, the automatic feeding device must be designed as a detachable structure. This is also necessary in view of the fact that the close spacing between the sheet feeding station c and the thick original supporting carriage a permits interference therebetween. Even in a model having no automatic sheet feeding (FIG. 2), interference of the sheet original feeding device would occur when a portion of a large-sized thick original is to be copied. In fact, the practical model shown there is also so designed. This would necessarily result in reduced operability. Moreover, the requirement for even the sheet original inserting portion to be reciprocable leads to an increased stroke of the reciprocating movement.
If commercially broad requirements are to be met, it would be possible to think out of this embodiment a less expensive model from which the sheet feeding station of such special specification is removed. This model, however, would be irrational because it would have an unnecessarily rigid reciprocating guide device which would in turn lead to an unnecessarily great stroke of reciprocation.
A stationary original carriage type model (in which the optical system is reciprocable) is disclosed in U.S. Pat. No. 3,833,296. In an embodiment thereof, interference tends to occur between the original supporting portion and the sheet original feeding station as in the above-described examples, and the stroke of reciprocation of the optical system is great. Another embodiment shown there is complex in construction of the optical system and accordingly, not practical from the manufacturing point of view.
In addition, the concepts disclosed in these models cannot be developed beyond the automatic sheet original feeding device.